Rhode Island’s air quality continues to improve

Matching a long-term trend that air quality is improving, New Englanders experienced a decrease in the number of unhealthy air-quality days this year. In Rhode Island, there were seven unhealthy ozone days in 2013, compared to 12 last summer, according to the Environmental Protection Agency.

The findings are based on preliminary data collected between April and September. Monitors recorded 20 days when ozone levels in New England exceeded healthy levels. In 2012, there were a total of 29 unhealthy days. The trend in unhealthful days over the past 30 years is substantially downward. The trend is due to reduction in the emissions that form ozone.

The most unhealthy days in New England in 2013 was 17 days in Connecticut. The least was zero in Vermont. Massachusetts had three unhealthy ozone days.

Although the number of unhealthy days may vary from year to year due to weather conditions, New England has experienced a decreasing number of unhealthy days. In 1983, New England had 113 unhealthy days.

Ground-level ozone is the main ingredient of smog. Ozone levels are unhealthy when average concentrations exceed 0.075 parts per million over an 8-hour period. Ground-level ozone is formed when volatile organic compounds and oxides of nitrogen chemically react in the presence of sunlight. Cars, trucks and motorcycles give off the majority of the pollution that makes smog. Fossil fuels burning at electric power plants also emit substantial amounts of smog-making pollution. Gas stations, print shops, paints, household cleaners and gas-powered lawn equipment also contribute to smog formation.